Automatic ringing device for telephone-exchange systems.



No. 838,244. PATENTED DEC. 11, 1906.

w. W. DBAN. AUTOMATIC RINGING DEVICE FOR TELEPHONBEXOHANG E SYSTEMS. APPLICATION FILED JAN. 16, 1906.

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No. 838,244. PATENTED DEC. 11, 1906.

W. W. DEAN. AUTOMATIC RINGING DEVICE FOR TELEPHONE EXCHANGE SYSTEMS.,

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ga wavd'oz No. 838,244. PATENTED DEC. 11, 1906.

W. W. DEAN.

AUTOMATIC RINGING DEVICE FOR TELEPHONE EXCHANGE SYSTEMS.

urmouron FILED JAN. 16. 1906.

3 SHEETS-SHEET 3.

aweni'oz UNITED S AT S PATENT OFFICE.

WILLIAM W. DEAN, OF ELYRIA, OHIO, ASSIGNOR TO THE DEAN ELECTRIC COMPANY, OF ELYRIA, OHIO, A CORPORATION OF OHIO.

AUTOMATIC RINGING DEVICE FOR TELEPHONE-EXCHANGE SYSTEMSv Specification of Letters Patent.

Patented Dec. 11, 1903.

Application filed January 16. 1906. Serial No. 296.287.

To all whom it may concern:

Be it known that I, WILLIAM W. DEAN, a citizen of the United .States, residing at Elyria, in the county of Lorain and State of Ohio, have invented certain newand useful Improvements in Automatic Ringing Devices for Telephone-Exchange Systems, of

use in exchange systems in connection with what is known asmacl1ine-ringing.

In all except the very smallest exchanges it is now usual to provide either a ringinggenerator or some form of pole-changer wherefrom current ma be derived for actuating the subscribers ells. This current is applied to the subscribers lines through a switch -mechanism adapted to cut as its source except during "the periodof actual ringing, the usual form of switch employed being a manually-operated key. Such a key, however, must either be held in ringing position b an operator, ceasing its function when t e 0 erator relaxes her hold, or if it is' to remain own it must be fitted with some special holding .appliance or latch; A latch of this kind, which depends for its tripdping upon a further act of the operator, Won not be in accord with good practice,"s1nce the operator's attention might be 'otherwise bestowed until after the calledsubscriber had answered, the annoying result of passing noisy generator-current through his recei'ver until the key could be finally released.- Of course'wliere supervisory signals are em-' ployed this condition would be guarded against in a degree, but not altogether so it has been suggested to control the key or switch through a .mechanism which will res ond to the calledesubscribers act in taking own his receiver to thereupon immediately release the ringing-generator.-

So far as I know none of the ringing systerns now in use has given entire satisfaction One reason for this lies in the necessity for ringing through the governing-relay, which is so wound as to be unresponsive to the small volume of current permitted to pass by the normal high resistance of the subscribers line with the ringer included. It is impossible to construct this magnet so that it will be devoid of resistance and self-inductance, and hence there must always be a certain drop in efliciency of ringing where it is employed.

- My present invention is in the nature of an improvement on the systems heretofore in use.

It contemplates the ap lication of ringingcurrentto the wante subscribers line through a suitable switch orkey and the maintenance of the condition so until. the called subscriber shall ave answered his telephone, whereupon the source of ringing-current will be immediately disconnecte It contemplates also the use of selector or So-called harmonic, ringing-current of dif'-- ferent frequencies, which has heretofore been impossible, for the reason that with a magnet,

in the ringing-circuit no proper, adjustment of either the ma net, the circuit, or of the roduced such as a tripping-magnet I have mentioned,

current itself "con (1 be had. Since :the s'elfinductance of a circuit varies with the freqgliency of the current employed, it is obvious t at a magnet-winding which would be suitable for a low-frequency current might and probably would seriously impede the passage of high-frequency current.

According to my electromagnet comesat any time in the path of ringing-current. Hence the hi hest'efiinected until the 'wanted subscriber answers,

when it will be automatically disconnected by means of a responsive device having'no self-inductance, but quick and positive in its action. Such a responsive device I describe resent invention no electromagn'et 1s emp oyed, or at least no' rod and illustrate herein asa thermic con troller. This may take the form of a relay,

or it may directly control the detent' orilatch of the switch. In the bestfeinbodimnt which I have so far devised it""comprises a a ringing device applied thereto.

similar diagram showing a modified form of;

, rocking lever, a triangular strain-plate, and

a pair of balanced wires connected from opposite ends of the strain-plate to points on Opposite sides of the pivot of the lever. of these wires is included in the generatorcircuit; but the other is insulated therefrom. The size of the wires is such and the parts are so adjusted that suflicient ringing-cure rent may pass to actuate a subscribers bell without unduly heating the wire and without disturbing the balance established between the two opposite points on the lever. A rise in current in the generator-circuit, however, such as that occasioned by the removal of the subscribers receiver from its hook .and the consequent substitution of his low-resistance talking set for the high resistance ringer, will heat the wire on the generator side, so as to expand it, and thereby disturb the balance of the lever and move the same; This lever is used to control the switch.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a diagram showing two subscribers stations and a central station w th an operators cord-circuit thereatv and my Fig. 2 is a ringingdev-ice. Fig. Sis another similar diagram showing a further modification of the ringing device.

Referring to Fig. 1, A and A :are two subscribers" stations fitted-with the ;.usual tele-.

phones T, ringers Q, and ,switch-hoo-ks The resistance of the ringers is very much higher than that of the telephones. From eachstation the line-wires 1 and 2 pass to the cent-ralofiice, where they terminate in contacts of spring-jacks JJ, normally closed upon terminals connected to line-annunciators L L"an'd the main battery B. The system shown is provided with a common battery, and it is to he understood that although v this is shown iii several units-for convenience of illustration they are in reailty' all one and. p the same. Since the present invention does not concern itself with line-signals or battery connections or any of the other details ofa complete system, I have shown only the essent'iailshnd these in their simples-t forms;

Thus the line si nal-magnets are supposed to control-the litt e targets show-n, lifting the same into view when energized and dropping vthem zwhen d'e'ener'gized,

For the pmripose of interconnecting t lines through-rt cnnected, respectively, through the cord- 3 .4; '5 This circuit-is oonductively divided, inductivelycontni'uous, because of' theinsertionof a repeatingcoil I between shown.

I e spring j-acks-I iprpvide-the. plugs P 5P, havin tip and sleeve contacts visory signal-magnet S or S, represented in the same manner as the line signal-magnet ing and to retire their signals when theflow of current ceases, The plug P is'the answering-plug of the pair,'and associated with it is a listening-key, (not-shown) whereby the operator's telephone may be bridged across the cord conductors 3 4 in answerin calls. The plug P on'the other hand, is the calling-plug of the pair, and associated with it is a ringing-key K, which, with its as: sociatedparts, forms the subject of the present invention. This ringing-key is shown as the plunger 7c, having a cam-head adapted to be forced by the plunger between the pair of sprin s 7c P, which normally rest in contact with companion. springs in, but are thereby spread-apart, lifting the inner springs referred to and making contact with. outer springs 1: 1c. These outer j springs constitute the terminals of a circuit? 8 9, contain-' I ing the ringing-generator G. The inner springs 7c 70 form terminals for the conductors 5 6 of the cord-circuits, and the middle or active springs k k are connected,- respectively, to the tip and sleeveof thecazllingfor example, by means of a-pin and slot, as The leveris pivoted in its middleand at its lower end has an inclinedcamrface which rides up over a similar faceon theend of the levcr k when the plunger Zcis pushed in.

The thermic controller K consists-essentially, of the two thinwires 910, the strainplate is", and the detent-lever k The strainplate carries pins is -7c on its opposite ends and has a spring is attached at an intermedi ate point. "This strainplate may 'eitherlbe of insulating material or of =metal, with the pins insulated. The'detejnt lever k alsooar- I ries two insulated pins 10 76 onopposite sides "of its pivot id". The wires "9 10am stretched between the pins on the-strainplate and'the pins on the lever and aresondjusted that under normal, conditions and whenin disuse the parts willstand as shown in'Figi 1. The wire. 9 formsa part of. the. generator-circuit 7 8 9 G, as already pointed out but the Wire'10 is completely insulated. Both-wires are maintained taut' by the-constant ull on thes ring is on the strainplate Changes in external temperature,

as of :the surrounding atmosphere, on parts the ringer Q and produces-sounding of; the

In accordance the lever for this of the ap aratus do not afiect the adjustment of the thermic controller, for all such changes afiect the two wires 9 and 10 equall and since they are both maintained equally taut the device may be called self-compen:

sating'. Should one wire become hotter than the other, however, this balance would bede-j I stroyed and the lever k would be tilted. This e condition brought about when the is t called subscriber answers,- as

out in my statement of operation.

Assuming that subscriber A desires to talk with subscriber A he rernoves his telephone from the hook, the latter rises, the line-circuit is. thereby closed, and currentjfrom the main battery B traverses the line and'its signal-magnet L ,energizing this magnet so that after testing the jack J (if she is working on a multiple board) and serts' the plug P key K. The cam-head of the plunger =k thereupon asses between the springs k- 7c, spreading t em apart, as already described, and the lever k at the same time rocks upon its pivot until its lower end latches behind the deteht-hook onthe end of the leverk The spring k permits sufiicient movement of latching, pulls the lever up firmly, lc is maintained inposition, and the enerator G is left connected with the subscri 'erfs line through the following circuit: sleeve of plug, jack J, line-wire 2, ringer Q, line-wire 1', jack J, tip of-plug, k, 7c. -7,'9, 8-,

G. Current flowing in this cireuit actuates' finding it idle she 1nsubscribers gongs. modern practice in machine-ringing I prefer to include in the circuit 7 8.9 a contlnuousl driven commutator which will alternate y make andbreak the generator-circuit, or atleast divert the current from the ringingkeys, giving, say, two seconds on and four seconds of? and this ringing will persistuntil subscriber A removes his receiver from the hook. The resistance of his ringer Q,

of any large quantity of current. Hence the wire 9 of the thermic controller remains cool.

i When the subscriber takes down his receiver,

however, he closes a shunt around his ringer through the telephone set '1, which has a relatively low resistance.

ver k is tilted on its pivot k by virtue ,of the the I" will now point Iwire9 again cools perceiving the therein and pushes. down the ;magnets,IJ I! and leaving a tion for another call.

,- IhlTig. 2 I have shown a'modificationofin succession. This condition taken with the line resistance, is sufiicient to prevent the passage The result of this 1s that current immediately rises in the circonstant tension of the spring has This tilting throws down the detent end of the lever, re eases the lower end of the rocking leverk",

and, theplunger k is thereupon pern-litted to be fo-rced outwardly bythe springskf-k As these springs :come together they generatowterminal's 1c";

Ieave the k and again ma-ke contactfwiththeir, companion springs k k,

reupon'lreestablishing the 'jobntinuitymf the cord circuit which before was interrupted in orderv lac-prevent irin'ging back over theconductors 3 4' to the calling-station A,

where the 'subscrib rhas had the receivert his ear whilewaiting. As soon as the thermic controller" has' released. the key K. the. if and the detent-lever" re sumes its'normal ositionl The operatp'r is now informed display of the targets} of both'supervisery ma ets S swhat th call has been answered and thesubscribers and hung up their telepho'nesythse targets fallback, and thereupon. the operator-pulls the plugs? P, reconnecting the linesignal 'par s i ct are conversing. ;When rth ey have ,finished;

' directly control thedetentl ever Icfi-but controls the same through the ihtermediation' of an electromagnet la.

leverfk tilted; The thermic-controller as acts as a relay K.v The wire-9 circuit of the ringingg enerator Gr, while the wire 10 is insulated.

he 0 erationis the same as in Fig. 1.

In igi -3 I have shown another'modification,.-wherein the thermic controller works the detent-l ever I hrou gh the intermediation of air or gas under'pressure. Here X is the receiver or gas tank, charged to a consid erable pressure and having a pipe as connectingit with a chamber at, containing the p hose circurtrl? 13 is completed to the maih battery B; when the but thereafter so that the plunger lever is of the w v v to control the magnet If;ahd'thelattercontrols the lever 713 which "controls the .ro cking =1p1mger=k bf the ringing-key of the thermic controller or relay-:is connected',! a s before, in the piston x connected to one end of the dew tent-lever lc valve at, having its stern connected to one end of the lever k of the thermic controller. In

Inserted in the pipezeis axslide its normal position, with the parts as shown 3 in Fig. 3-, is open tothe outer air and in communication with the chamber as", while that portion of the pipe :1; leading to the tank X is shut off. Assuming the'subscribers to be connected as in the operation of Fig. 1 and subscriber A to have answered, the operation of'this modifled arrangement lS'iLS follows: Current from generator G rises in the circuit 7 8 9, heating the wire 9, as before, so that it expands very considerably. This expansioncauses the lever k to tilton its pivot k lifting the slidethe exhaust-channel-ac of this valve.

, non;i nductive controllerres onsive to .ci1rmade in matters of det'ail and this invention distinctly understood that fall non es'sential adapted ,to be actuated theresultant rise I substantiallyas}described.

-2. In,,a telephone -exchange' system, a I

. a thermic controlljer therefor included in cira ing key, and a non-inductive control- I ing-key, ,fa. non-inductive ,controller therefor vresponsiye to changes n. current, and means ,contro led,.by a s ubscriber to produce a I sent-ally as. described.

sa Q J ZRsQm c n e-o current the same irom tlie suhscribers I'ine,,snbstan- 5 5 I I valve a? until the. through-channel an? renders the passageay continiious'from the receiver or tank tow-the, chamber a". Pressure being thus appliedt0 the under side of the piston the latter is forced up in thechamber, the lever 7g is tilted, the rocking leverJc is re-. leased, and the plunger k springs out, cutting off the generator and restahlishing the continuity of the cord-circuit. Y

Iam. ware that many changes may be m y .b mb9t1 e i many .er r both of circults and apparatus ;.'but I Wish it my claims. I

Hayi ng thus described my inveptiomwhat changes are Within the scope,andpnryieyy'of I claim andidesireto secure byLettersPfzitent, is

1 1.. Ina telephone-exchange systerna subscribers station and a central station. and a line-circuit interconnectingithem, a signal device of highresistance and a, telephone of across the. line at the sub s cr-ibers station, means to apply signalingecurrent to the line at the central station for actuating Y the ringer, means at'the substation toblose the .telephon'evcirc uit. inransyyeringa call, and a thermic controller. at thecntral station in current to remoye t'he same from the l ine,

source oi; ringing-cement, a ringing-key, and

cuitj with the source, of riiigirig-current.

I I 3. In I a telephoneeexchange system a li nef ling evice, therefor responsive to changes in line-current.

4. In atelephone-exch'ange system a ring scribed.

change. in-thecurrent in answering a call, sub- 5. ate] phoneexchangezsystem a subscribers-I line;means for.. ap lying ringingcur rentithereto ;..'n1eans,,at t e subscribers swering a 'gca l a non-indnctiye meansresponsive to said change n; current ,for ,removmg tially as describeda I circuit having. a -signal :flQVlCG connected thereto, a. Source ofsignahngscurrent, and a rent in the line for determinmg the applica- 6. .Inja,telephoneexchangesystem, a line- I I I prising a key or SWItOh, a detent therefor, a

tion of. the signaling-current thereto.

7., In a telephone-exchange system a s .ub 'scribersstation and a central statlon and a line-circuit interconnecting them, a rihger normally connected to thelme at the su b-. l

scribers station, meansat the central station .to connect a source of rmglng-currenttothe line, and a non-inductive controllerfor said means responsive to changes intheringing- I duce 'such' achange in the r nging-curreli as Will affect the controller to discrjihiiect' the source from the line, snb'stantia'lly'as d'e- I 3 In a telephone-exchanges stem, a i

I rial-circuit, a isource I of s gna big-current,

the s gmeans forconnectingsaid sourceto I I nalsc rcuit, and a non-inductive c'gu' t'rollmg' devicefor said. means connected thereby to:

said signalecircuitto be operated by current therein.

. 9. In a telephone system aringing device comprising a switch, a detentfor the switch, and non-m g etic 'c'ontrolflerffbr'the detent, substantially as described.

'10-. In a telephone 'systema non-inductiye non-magnetic 1 controller for fringingcircuits,

comprising'a strain-plate, an operatlng-leyer, a. pair of balanced wires extending between 'the strain-plate and :operatiti'g lever, 1and means, for' connecting one'oif the wires, l njthe ringing-circnittobe affe qte I' by' any rise of current therein, substantially asgdes'cribed.

' 11; In a telephpneexphange. system an operatorfs automatic fining device, 'co'mprising a manually-opera le I key, I a detent therefor, and nongind ictiye means contrqI led by thecalled subscriber to trip saiddete'nt and release the key, substantially as ,de-

scribed. I I 12.' In a telephone-exchangeIsystem.jan oFeratiye ringing d6V1CG, comprls n "a manua l yoperable key, j a fdetent there arena 0, nonsinductiye controller for the I detent, c0n-.

nec'ted to line through the keyandadapted to be affected b -cu'rrent in the r inging-ci'n cnit, substantially as described.

13. In 'a telephone-exchange sy s' t em an. operators automatic ringing device, com-- prising a key, a detent'ther'efor, and a nonma' netic controller for the detent, substam tial y as described.

14. In a? telephone-exchange. system anoperators 'automatic ringing I deyic' prising a key, a detent therefor,' Irieans.'for

tripping II c'ontro er for said means,

scribe 15. In a telephone-exchange system an ubstantial said detent, and a 'nonfmaglne'tic yI as 'Izo opera'tors automatic ringing device, comnested through the switch to lineih the ringling-circuit, s'ubstantiallyas described.

16. In a"telphon'e signaling system, the

combination with a plurality of subscribers stations and an exchangestatlon, slgna l-reof ag e nerator at the exchange, wringingkey controller for"said-key in the generator-ciruit' i 7- ceiving devices zit-the subscribers stations, '18. a telephone eiichang system, a

line, a source of rmgin current, a key-switch f0r.c1'0si1w' the circuit of said generator to and-a tgheimic contr'oler therefor arranged :5

said signaireeeiving devices,' and athern al to be irresponsiye to atmospheric changesi i but responsive tocurrerit changes iii the line.

i I e I11 testimony whereof I aflix my signature j 17 In a. telephbndwxchange s l stem, 3 in presence of two Witnesses.

source of rin in current',a'ri-n in wey, an 3 a balanced gthe imicjcontrollei .iriluded 'in' the circuit of said source, said tghern' ic. con- 2 troller being irresponsive- -to atmospheric changes but oper51tive by: chsinges of current;

Witnesses: 3

A. J. ROBERTS,

I. i" GEO. A. SoovILLE. 

